👉The name virus that means venom or poisonous fluid was given by
Dmitri Ivanowsky (1892) recognised certain microbes as causal organism
of the mosaic disease of tobacco (Figure 2.6a). These were found to be
smaller than bacteria because they passed through bacteria-proof filters.
👉M.W. Beijerinek (1898) demonstrated that the extract of the infected plants
of tobacco could cause infection in healthy plants and called the fluid as
Contagium vivum fluidum (infectious living fluid).
👉W.M. Stanley (1935)
showed that viruses could be crystallised and crystals consist largely of
proteins. They are inert outside their specific host cell. Viruses are obligate
parasites.